Animal research is of vital importance to studies of human diseases. Research in transgenic mice is cost-effective and is becoming a screening standard at the FDA. The proposed research will develop a small animal-implantable cardiac physiology research monitor, with high fidelity pressure-volume and ECG sensors mounted on a 1F catheter. Cardiovascular parameters will be transmitted to an external data collection module for up to 3 months. The system will be catheter-based, specifically designed for cardiovascular research, but could be applied to any organ research, including the brain, the bladder, and major blood vessels. The system is designed to allow a mouse to return to a normal physiological state after implantation. Phase I will develop and evaluate vacuum-sealed ultra-miniature pressure transducers and control circuitry using a pulsatile mouse heart simulator. The standardization and temperature compensation will be achieved using either laser-trimmed resistors or signal conditioning CMOS technology. Implant life will be maximized by applying pulsed excitation techniques. A complete prototype system will be tested. Phase II will miniaturize the implanted package, and test it in animals. Studies will include optimization of data sampling rates, operational life, and characterization of tissue-device interaction at gross and histological levels.